The Regions Forests

Biotic factors influencing the forest involve animals (insects, birds, mammals, etc.), plants (fungi, competing vegetation, etc.), and, of course, the trees themselves. In this book, trees are our principal concern, though other biotic components play significant roles in the development of forests.

More than 60 forest-cover types have been recognized by the Society of American Foresters as occurring in the South. These are generally grouped into nine classes. The oak-hickory-pine type, the most widespread, covers 21.7 million acres.

Acreages garnered from survey records of the U.S. Forest Service show the four principal southern pines (longleaf, slash, loblolly, and shortleaf) to be the primary species on more than 69 million acres. Most of this acreage is in the Coastal Plain, some 70% covered by loblolly or shortleaf pines. The lesser southern pines (pond, Virginia, sand, pitch, spruce, and table-mountain) occur on

Figure 1.7 Soil regions of the southern United States: (1) red and yellow podzolics, (2) grey-brown podzolics, (3) podzols, (4) lithosols, (5) rendzina, (6) weisenboden, ground-water podzol, and half-bog, (7) bog, (8) alluvium, and (9) planosols. More recently a highly technical International Classification System has been developed. (after USDA, 1957)6

Figure 1.7 Soil regions of the southern United States: (1) red and yellow podzolics, (2) grey-brown podzolics, (3) podzols, (4) lithosols, (5) rendzina, (6) weisenboden, ground-water podzol, and half-bog, (7) bog, (8) alluvium, and (9) planosols. More recently a highly technical International Classification System has been developed. (after USDA, 1957)6

5.5 million acres in the Coastal Plain, Piedmont, and Appalachian provinces. The oaks and pines together are tallied on 30 million acres and the oaks and hickories on 86 million acres. Baldcypress stands, with their associated gums and oaks, comprise 34.3 million acres in the South. The elm-ash-cottonwood type of the wet areas and the beech-birch-maple predominate on 4 million and 3.2 million acres, respectively. The latter type predominates on the midslopes of the mountains and occasionally along the edges of the rivers of the Coastal Plain. White pines and hemlocks, the latter the climax species under pioneer white pines, are mapped on about a third of a million acres; the spruce and fir forests, exclusively in the upper reaches of the Appalachians, occur on another 42,000 acres.

Eastern redcedar (a juniper) spreads out rather evenly in all provinces, totaling about 2.5 million acres, excluding the Nashville Basin and the Ozark Cedar Glades. Eastern redcedar and bunch grass together dominate the cedar glades of the Nashville Basin in Tennessee. In the Ozarks, where redcedar once was a predominant species, its presence is now much less frequent. In the cedar brakes of the Hill Country of central Texas, Ashe and Pinchot junipers, appearing as redcedars to the inexperienced, honor in their names a dendrologist and the father of American forestry, respectively. Mesquite, an import from South Texas and Mexico brought northward as seeds in the stomachs of cattle during their long drives to market stockyards or kept low in numbers by frequent surface fires, now accompanies the junipers, as do post oaks and other scrub oaks, on many sites. The juniper trees, with their red-colored fragrant wood, may form pure stands.

The totals, allowing for generous rounding of figures, indicate that about 128 million forested acres occur in the Coastal Plain, 33 million in the Piedmont province, 39 million in the Appalachian Mountains, 10 million in the Interior Low Plateaus of Kentucky and Tennessee, and 25.5 million

Color Soil For Appalachian Mountains
Figure 1.8 Sampling tubes enable study of the soil to depths of several feet below the surface of the ground. Extracted from the pipe onto a tray, texture, color, and structure can be observed and samples from various depths carried to a laboratory for chemical, physical, and biological analysis.
Where Are Oak Hickory Pine Forests

Figure 1.9 Potential vegetation types of the Southern Forest Region: (1) oak-hickory-pine, (2) longleaf-loblolly-slash pines, (3) oak-ash-hickory-yellow-poplar-maple-basswood-Buckeye-beech, (4) oak-sweetgum-baldcypress-tupelo, (5) beech-birch-maple-hemlock, (6) oak-hickory, (7) coastal prairie, (8) Everglades grasses, and (9) redcedar-bunch grass (cedar glade). (after USDA, 1963; and A.W. Kuchler, 1964)7

Figure 1.9 Potential vegetation types of the Southern Forest Region: (1) oak-hickory-pine, (2) longleaf-loblolly-slash pines, (3) oak-ash-hickory-yellow-poplar-maple-basswood-Buckeye-beech, (4) oak-sweetgum-baldcypress-tupelo, (5) beech-birch-maple-hemlock, (6) oak-hickory, (7) coastal prairie, (8) Everglades grasses, and (9) redcedar-bunch grass (cedar glade). (after USDA, 1963; and A.W. Kuchler, 1964)7

in the Interior Highlands of Arkansas and Missouri. The grand total of the southern forests, changing daily as land is reclaimed to woodlands and converted from timberlands to other uses, now approximates 235.5 million acres, or 368 thousand square miles. That is the equivalent of the gross area of the five New England states plus the three large Lake States (Michigan, Wisconsin, and Minnesota), plus Indiana and another some two thousand square miles. The pre-Columbian forests of the South could have encompassed 400,000 square miles.

The late-successional climax oak-hickory forests were most frequently found by the explorers and pioneers as they roamed these woods in the Piedmont and in the upper Coastal Plain from East Texas to New Jersey. This cover type also predominates in the Missouri Ozarks. The oaks and hickories (without the pines) are the common species of the forested biomes of western Kentucky and Tennessee, of the higher elevations in the Ozarks, and of the Post Oak Belt's ecotone; often called the tension zone, just west of the pineries of East Texas.

Longleaf pine-loblolly pine-slash pine form the overstory vegetation in the lower Coastal Plain, extending from southern South Carolina into the pineries of Texas. Often fire climax, and certainly present because of fire history, in the absence of fire, these stands give way to the oak-hickory climax cover type.

In the rolling hills from Maryland to the Bluffs of Mississippi, a complex forest often develops. It may consist of mixtures of several oaks, ash, several hickories, yellow-poplar, maple, basswood, buckeye, and beech. Among these species are both climax trees, such as the oaks and hickories, and intolerant pioneer plants like yellow-poplar. The stands are thus uneven-aged as well as mixed. Openings created by man or nature in a climax stand provide conditions that encourage light-demanding hardwoods to germinate and survive.

The river bottoms, often spreading out for miles as a fan from both sides of water courses, exhibit mixtures of oaks, sweetgum, baldcypress, and tupelo. While these predominate, perhaps a hundred lesser species also occur. (Heartwood from the sweetgum trees growing in these lowlands, in contrast to those on high, dry hills, is a rich reddish-brown; hence, the tree is often referred to as redgum. When used for furniture and millwork, the wood is marketed by lumbermen as figured gum, along with tupelo found on similar sites.) About 25% of the Coastal Plain forests originally were bottomland types. Higher-value use of the land, especially for agricultural crops like cotton and soybeans, has lately diminished the bottomland acreage growing fine hardwoods and bald-cypress trees.

Among the unusual wet-site forests are the pond pines in the pocosins—Indian for "swamp-on-a-hill"—that survive repeated wildfires raging through the organic soils when the fibrous surface stratum dries out. Normally too waterlogged for good tree growth, when dry the accumulation of pine needles is highly flammable. Atlantic white-cedar also occurs as dense, pure stands in pocosin swamps. These wetlands, covering a few to several thousand acres in area, may have developed where dunes along shorelines have affected waterflow, the ponds filling with organic matter that decomposes into soft black muck and brown fibrous peat.

Domes of baldcypress—another unusual wet-site biome—occur in lower peninsular Florida. These islands, with the taller trees in the center (the opposite of conventional isolated stands of trees), range in size from less than one to more than 100 acres. Variously attributed to fire, grazing, and drainage, the domes are surrounded by grassy savannas or by water.

Spruce pine, growing on the moist fringes surrounding longleaf pine stands not far inland from the Gulf of Mexico, is also associated with loblolly pine and hardwoods in the drainages of the Coastal Plain. Acreages and volumes available for harvest and marketing are so small that the species has had only minor attention. Little is known about its silvical characteristics.

Coastal prairies, frequently joining coastal estuaries of broadleaf trees and shrubs, are influenced by the storms that develop in the Gulf of Mexico. Cyclone winds and fire keep them treeless. Everglades, the extensive acreages of grasses at the southern tip of Florida, like the coastal prairies, also are generally without forests.

Figure 1.10 Periodically flooded estuary. Fluctuating water levels in coastal "lakes" like this one supporting baldcypress trees have become a major concern of the federal government with passage of the Coastal Zone Management Act.

Coastal savannas (treeless grassy plains) should not be confused with grassland types with scattered trees occurring farther west or the blackland prairies developed on calcareous parent material inland from the Gulf Coast. These latter dry savannas also interrupt the forests; such sites today find use as improved pastures.

Among the unusual dry-sites are the pine barrens of southern New Jersey that lie on the edge of the southern forest. Such xeric areas include vast acreages of sprout-reproduced, short-boled pitch pines in extensive zones called "plains." Scrub oaks and shortleaf pines compete with pitch pines on these excessively drained sites. The low-value hardwoods must be controlled if a new pine stand of any commercial value is to be regenerated. However, many prefer the barrens left for aesthetic reasons in their present condition. To accommodate that preference limits management intensity and, thus, the commercial value of these forests.

West Florida sandhills, covered with pure stands of low-grade longleaf pine prior to the harvest of the virgin forest, are also difficult xeric regeneration sites. Before seedlings are planted, sites should be prepared by removing the invading drought-hardy scrub hardwoods. Slash pine, which was also abundant in the droughty sandhills virgin forest, has been the preferred species for planting

Florida Pine Scrub

Figure 1.11 Remnant virgin longleaf pine-scrub oak forest cover type in the west Florida sandhills. Many such stands naturally regenerated to slash pine following the initial lumberman's harvest; other sites were planted to the latter species. Only recently has an interest in reestablishing longleaf pine on these lands become significant. (USDA Forest Service photo by E. A. Hebb, 1955)

Figure 1.11 Remnant virgin longleaf pine-scrub oak forest cover type in the west Florida sandhills. Many such stands naturally regenerated to slash pine following the initial lumberman's harvest; other sites were planted to the latter species. Only recently has an interest in reestablishing longleaf pine on these lands become significant. (USDA Forest Service photo by E. A. Hebb, 1955)

on these deep, coarse, sandy soils in the Panhandle of Florida, but longleaf pine is gaining in appeal as planting knowledge increases.

We now consider the zones of the region in some detail.

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  • Markus
    Where are oakhickorypine forests?
    7 years ago

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